Alignment and orientation detector for extrusion press dummy block



ARDNER 3,282,074 0 CTOR FOR EXTRUSION N DETE MY BL D. RIE

Nov. 1, 1966 ALIGNMENT AND O OGK PRESS DUM 5 Sheets-Sheet 1 Filed May 17, 1963 INVENTOR. Do/ynw GA D/YEI? Nov. 1, 1966 D. P. GARDNER 3,282,074

ALIGNMENT AND ORIENTATION DETECTOR FOR EXTRUSION PRESS DUMMY BLOCK Filed May 17, 1963 5 Sheets-Sheet 2 DONALD 1. 614900 A TTOF/VE'S Nov. 1, 1966 D. P. GARDNER 3,282,074

ALIGNMENT AND ORIENTATION DETECTOR FOR EXTRUSION PRESS DUMMY BLOCK Filed May 17, 1963 5 Sheets-Sheet 5 INVEN TOR. [701mm 2. GHQ YE? A rroe/veys United States Patent l 3,282,074 I ALIGNMENT AND ORTENTATHQN DETECTGR FOR EXTRUSEUN PRESS D BLOCK Donald ll. Gardner, lrondequoit, N.Y., assignor to Farrel Corporation, Rochester, N.Y., a corporation of Connecticut Filed May 17, 1963, ar. No. 281,174 18 Claims. (Cl. 72-21) This invention relates to extrusion presses and more particularly to means for sensing the presence, alignment and proper orientation of a dummy block and for permitting press operation when the dummy block is in position for the forward stroke of the ram and for stopping press operation when it is not properly located.

An extrusion press operates to force metal through a die which gives it the desired shape. Such a press may include a container for holding the billet of hot solid metal, a billet leader for lifting the billet into position for insertion into the container, a ram which moves the billet off the billet loader and into the container and which enters the container at the rear end to force the metal out through a die which is shaped to generate the desired cross section of the extrusion at the other end, and an end platten which holds the die.

In operation, the working tool, commonly called a dummy block is interposed between the hot billet and the ram. It protects the ram from the heat of the billet. Moreover it is the tool which actually causes the extrusion since the forward portion of its circumference is machined within close tolerance to just fit the bore of the container so that the metal will be forced out ahead of it and the ram and cannot leak around the dummy block to foul the ram during the extrusion stroke.

It is imperative that this dummy block not only be present, but be properly aligned and oriented before the extrusion is started and that this aligned orientation be maintained throughout the extrusion and particularly during the critical initial portion of the ram stroke while the billet and dummy block are hit by the moving ram and knocked off the loader into the container. If the dummy block loses its initially proper orientation during this handling, this must either be immediately sensed and the press operation stopped or not only the press but the operator will be subjected to serious danger.

It is an object of the invention to provide means which will insure that the dummy block is aligned with the container and ram just before and during the rams forward movement to hit and shove it into the container.

It is an object of the invention to provide means which will insure that the dummy block is in its proper orientation just before and during the initial advance of the press ram immediately preceding the extrusion stroke.

It is an object of the invention to provide sensing means for discriminating between the proper and improper alignment and orientations of the dummy block.

It is an object of this invention to provide these sensing means in combination with a dummy block which facilitates the aforementioned discrimination.

It is an object of the invention to provide means which can perform these functions dependably notwithstanding the increasingly rapid press cycling required by modern production requirements and means which are, at the same time, sufficiently simple to be both economically feasible and trouble-free in operation and which thus dldzfiwi Patented Nov. 1, 1966 achieve commercial practicability and usefulness in the daily operation of extrusion presses.

In brief, and according to one embodiment of the invention, a dummy block is provided with a counterbored rear face and preferably the counterbore is aligned with the block axis. Sensing means include a projection which extends from the forward face of the press ram and, according to a preferable alternative, is axially aligned with the ram axis and thus with the counterbore when the dummy block is aligned for insertion into the con tainer. This projection is connected to actuate a switch when depressed.

In operation, the press ram moves forward, hits the dummy block, and shoves it with the billet ahead of it, off the billet loader and into the container for the extrusion stroke. If the dummy block is supported on the loader in proper alignment with the press container and if it is oriented with the closely machined forward portion against the hot billet and with the rear face toward the ram, the projection member will be received by the counterbore of the dummy block rear face. If the dummy block is not knocked out of alignment when hit by the ram, or when shoved off the loader, the projection rnemher will continue to be received by the counterbore throughout the loading operation. The switch will not be actuated and the high pressure extrusion will be allowed to commence.

But, when the dummy block is missing, the ram and projection will continue until the projection member contacts with the end of the billet, which will depress it thus actuating the switch to stop further press operation. Likewise, when the dummy block is placed backward on the loader and so misoriented with its rear face toward the hot billet and front face toward the ram, the projection member will encounter an uncounterbored end surface and will be depressed to actuate the switch and stop further press operation. Even when the dummy block is present and properly oriented, and initially in correct alignment, but is then knocked askew when hit by the ram or shifted from the loader to the container, the projection member will sense the misalignment by contacting an uncounterbored portion of the rear face. This detector is thus useful with the fast cycling on the modern presses where the high speeds of the billet loader and ram cause rapid accelerations of the billet and dummy block in the loading operation and aggravate these serious problems. For example, a dummy block which has started its lift on the billet loader in correct alignment may be thrown out of position by the speed of a loader, or knocked out of position when bounced by the ram when it initially contacts the dummy block, or, as sometimes happens, when it re-contacts the dummy block after having left it during its sudden powered de-celeration to the slow extrusion speed.

The control means operated by the projection member sensing means may include a switch and a rod generally aligned with the ram axis and leading through the ram to actuate a toggle block in response to depression of the projection member. The toggle block, in turn, may actuate a rod extending at a generally right angle to the plane of the first rod. This rod may directly operate a microswitch connected into otherwise conventional press circuits to stop further operation.

Alternatively, the control means connecting the projection member to a switch may include a pneumatic -valve is open.

line. At the ram head of the line, the projection member operates a venting valve so that, when it is depressed, the valve and thereby the line is opened to the atmosphere, but is otherwise closed. Air is supplied to the pneumatic line through a regulated source and a metering restriction so that pressure is maintained against normal leakage, but is substantially reduced when the venting A pressure sensitive pneumatic switch is connected to the line so that, upon a drop in pressure, the switch is actuated and the press is caused to stop.

The best mode presently contemplated by the inventor for carrying out his invention is given in the following detailed description and in the following drawings in which:

FIGURE 1 is a side partial sectional view of one embodiment of the invention with a schematic drawing;

FIGURE 2 is a sectional detailed view of the projection member of the embodiment of FIGURE 1 juxtaposed with a dummy block constructed according to this invention;

FIGURE 3 is another sectioned detailed view of the projection member embodiment of FIGURE 1 juxtaposed with the dummy block;

FIGURE 4 is a sectional view taken generally along lines 44 in FIGURE 2;

FIGURE 5 is a side and partial sectional view of an alternative embodiment of this invention;

FIGURE 6 is a sectioned detailed view of a portion of the embodiment of FIGURE 5;

FIGURE 7 is a view of the end platen assembly and a billet loader of an extrusion press taken along the press bed; and

FIGURE 8 is a sectioned detailed view of another embodiment of the projection member.

As one of its practical achievements, this invention including the dummy block and the sensing and control means, may be incorporated into standard extrusion presses which may be of conventional construction except as is explained below. While it is useful in providing a safety interlock on manually or semimanually operated presses, it has special usefulness as a part of automatic cycling control and press systems.

A press bed 1 supports an end platen assembly 2 afiixed to tie rods 3 and having ways 4. The end platen assembly includes the usual die-slide assembly 5, including a die, and its hydraulic motor 6, shear assembly '7 and its hydraulic motor 8. The ways 4 support the container 10 which is typically fitted with alloy steel liners which define the container bore and which are machined to close tolerances and hardened to withstand extrusion wear. As explained above, the dummy block is the tool which works inside this hardened alloy steel liner at enormous pressures to force the hot solid metal of the billet to flow through the die. The billet loader assembly 11 may include a cradle assembly 12 which receives the billet 13 and the dummy block 14 from a ramp 15. The cradle is actuated by hydraulic motor 16 and carries both billet and dummy block into position for insertion into the container and its bore 17 in which position the billet and dummy block are aligned with the container. The press ram 18 is mounted on the cross head 19 in axial alignment with the container and powered conventionally.

According to the invention, a dummy block 14 has a forward or leading portion 20 sized to just fit the alloy steel liners 9 of the container 10 to close tolerance so as to wipe the liners and prevent any back flow of the hot plastic billet metal during extrusion and a rear portion 21 which is slightly smaller in diameter than the container bore. The dummy block has an uncounterbored or substantially fiat front end face 22. The dummy block rear end face 23 is provided with a counterbore 24. This counterbore is preferably generally cylindrical as shown in FIG. 2 and of suliicient depth and diameter to receive a projection member 25 which extends from the forward tween the front and rear face of a dummy block, constructed as described above, and between the rear dummy block face and a billet end or face. It includes counterbore sensing means including projection member 25 and control means including a switch 28 or 29 interconnected to the projection member. It can serve as a protective device for precluding a press operation with the dummy block missing, misoriented and reversed, or misaligned and out of line and thus prevent the danger, damage and production delay that would result from the application of extrusion pressures under any of these conditions. Not only can proper extrusion be obtained only when the dummy block is axially aligned with the bore 17 of the container and oriented so that its close fitting forward portion 20 will enter the container first but, under the enormous forces involved in forcing solid metal to flow through a die, even the parts of a massive press can be sprung or damaged by a tilted or jammed dummy block.

The projection member 25 may have a plug 30 threaded or otherwise fastened into the ram and aligned axially with the ram axis and centrally located through the front ram end face. It may include a guard portion 31 around the axially movable projection member to prevent damage to the stem portion 32 which may be provided with a rounded cap 33 to minimize the chance of damage should it be struck a sideward blow. This stern portion is depressed by contacting an uncounterbored face or end which will also be referred to herein as a flat face or end. It should be understood that it is flat only in the sense that it will not receive the projection member without depressing it. Such a flat face or end would be presented by the front face of the dummy block or by an end of the billet. The stem 32 is returned by spring 34 or its counterpart, in a second embodiment spring 35a, to an extended position. Means for juxtaposing the sensing means and the dummy block are provided by the same press hydraulic system that is conventionally used for advancing the ram, knocking the billet and dummy block off their loader and into the container for extrusion.

In view of the foregoing, it can be seen that when the ram head is advanced to contact the dummy block, the projection member maintains its position or location if the dummy block is present, properly oriented with the rear face rearward and properly aligned rather than askew so that the counterbore is axially aligned with the ram and its axis. In this condition, the dumy block is properly located for insertion into the container and subsequent extrusion and in this position the projection member is received by the counterbore in the rear dummy block end face. In this circumstance, the press operation is allowed to continue. Otherwise, if the dummy block is not present, or is misoriented or misaligned, the projection member will contact an uncounterbored or fiat surface and be depressed to stop or halt press operation. If the dummy block is present but not properly oriented, the projection member contacts the flat, that is to say the uncounterbored, front face of the dummy block; if the dummy block is present and properly oriented but not aligned, the projection contacts the flat uncounterbored portion of the rear dummy block face. If the dummy block is missing altogether, the projection member contacts a fiat billet end.

The control means operated by the projection member 25 include a switch which may for example be a pneumatic sensitive switch 28 as shown in FIG. 1. In this case, the stem 32 continues into rod 35 which is connected to valve 36 seating at 37 into the plug 39. When depressed the projection member opens the valve and allows air from a pneumatic line 38 to vent to the atmos- S phere through passageways 39. The pneumatic line 38 may include a bore through the ram stem that is equipped with appropriate end fittings and flexible copper tubing.

The pneumatic line 38 is supplied from a source through a regulator 40 and metering restriction 41. Together they supply sufficient air to build pressure in the line 38 and to maintain it against normal leakage. With the valve 36 closed and pressure in line 38, the pressure sensitive switch 28 is connected into otherwise known circuitry to permit press operation. But, when the projection member is depressed and valve 36 actuated, the pressure in line 38 drops and the pressure sensitive pneumatic switch 2% shifts. It is connected as an interlock in the control system and this stops the press operation and the ram advance.

Alternatively, as another example, the means interconnecting the projection member and the switch may be mechanical of which one embodiment is shown in FIGS. and 6. In this case, the stem 32 continues as rod 42 through a bore 42a in the ram stern generally along the ram axis to bear against a toggle block 43 pivoted at 44. Another rod 43a is mounted at generally right angles to red 42 and extends from the block to bear against switch 29, which may be located conveniently, for example, on the crosshead. Switch 29 is connected to serve as an interlock similarly to switch 28.

In view of the teaching of the above disclosure, the man skilled in the art will be able to use various equivalent embodiments in order to practice this invention. For example, and to gain increased protection for the movable projection member, including the stem portion 32, it may be recessed in the ram end face. In this case, the billet should be constructed with a pin, in place of a counterbore, to enter the recess of the ram end face. When properly oriented and aligned, it will depress the projection member which would, in this case, be connected to a switch serving as an interlock against further forward movement of the ram unless depressed. Another variation of the usually more desirable embodiment is shown in FIGURE 8, with plug 46 having a forward part 4-7 that also acts as a guard around the axially movable projection member, specifically stem portion 4-8, and a return spring 49 hearing against the back of valve 50 to normally urge it into the plug at seat 51. In presses using a mandrel and a tubular billet with a tubular dummy block and ram; the dummy block end face, in place of the centrally located counterbore, is provided with a counterbore in the shape of an annular recessed channel, offset from the dummy block axis. The projection member is similarly offset from the ram axis and carried by the ram end face that contacts the dummy block. When the dummy block is properly oriented, a portion of the recessed channel receives the projection member without depressing it. With the dummy block missing or oriented front face rearward, the projection member encounters the flat end surface of either billet end or dummy block front face and is depressed.

I claim:

1. In combination with an extrusion press having a billet loader, a ram and a container; a dummy block having a front face, a rear face, and sensing means mounted on the press for discriminating between said front and rear faces whereby the orientation of the dummy block may be detected.

2. In an extrusion press having a billet loader, a ram and a container; the combination of a dummy block having an uncounterbored front face and a counterbored rear face, sensing means mounted on the press for discriminating between said front and rear faces and means for juxtaposing said dummy block and said sensing means whereby the orientation of the dummy block may be detected.

3. In an extrusion press having a container, a ram, and a billet loader; the combination of a dummy block having a front face and a rear face, a sensing means carried in the front portion of the ram and including a projection member movable with respect to said ram, and means for juxtaposing the ram and thereby the sensing means including the projection member with the dummy block whereby the orientation of the dummy block may be detected.

4. An extrusion press including a container, a ram, a billet loader supporting a billet and a dummy block, and sensing means including a projection extending forward from the front face of the ram and movable with said ram and also with respect to said ram, control means including a switch for stopping and permitting the operation of the press and operated by said sensing means so that with the projection in a first position the switch is in a first position to permit press operation and so that with the projection in a second position the switch is in a second position to stop press operation.

5. An extrusion press including a container, a ram, a billet loader supporting a billet and a dummy block, and sensing means including a projection extending forward from the front face of the ram and movable with said ram and parallel to the ram axis, control means including a switch for stoppingand permitting the operation of the press and operated by said sensing means so that with the projection in an extended position the switch is in one position to permit press operation and so that with the projection in a depressed position the switch is in another position to stop press operation.

6. An extrusion press including a container, a ram, a billet loader supporting a billet having uncounterbored end faces and a dummy block having an uncounterbored front face and a counterbored rear face and sensing means including a projection extending forward from the front face of the ram and movable with said ram and with respect to said ram, said counterbore adapted to receive said projection, control means including a switch for stopping and permitting the operation of the press operated by said sensing means so that with the projection in an extended position the switch is in one position to permit press operation and so that with the projection in a depressed position the switch is in another position to stop press operation whereby press operation is permitted only while the dummy block is present and properly aligned with its forward face forward and its rear face rearward.

7. An extrusion press including a container, a ram, a billet loader supporting a billet having uncounterbored end faces and a dummy block having an uncounterbored front face and a counterbored rear face, and sensing means for discriminating between the dummy block rear face and the dummy block front face and between the dummy block rear face and a billet end including a projection extending forward from the ram, control means including a switch for stopping and permitting the operation of the press and operated by said sensing means so that with the projection in an extended position the switch is in one position to permit press operation and so that with the projection in a depressed position the switch is in another position to stop press operation whereby press operation is permitted oniy when the dummy block is present and properly orientated with its front face forward and its rear face rearward.

8. An extrusion press including a container, a ram, a billet loader supporting a billet having uncounterbored ends and a dummy block, said dummy block having an uncounterbored front face and a counterbored rear face, sensing means for discriminating between the dummy block rear face and the dummy block front face and between the dummy block rear face and a billet end, control means including a projection extending forward from the front face of the ram and movable with said ram and with respect to said ram and aligned axially with the dummy block counterbore while that block is supported by the billet loader in proper position for insertion into the container so that with the projection in an extended position the switch is in one position to permit press operation and so that with the projection in a depressed position the switch is in another position to stop press operation whereby press operation is permitted only when the dummy block is present and properly orientated with its front face forward and its rear face rearward and aligned in proper position for insertion into the container.

9. An extrusion press including a container, a ram, a billet loader supporting a billet having uncounterbored end faces and a dummy block, said dummy block having an uncounterbored front face and a counterbored rear face, sensing means for discriminating between the dummy block rear face and the dummy block front face and between the dummy block rear face and the billet rear face including a projection extending forward from the front face of the ram, said projection movable with said ram and with respect to said ram parallel to the ram axis, said dummy block counterbore and said projection both aligned axially with the ram axis when the dummy block is supported by the billet loader in proper position for insertion into the container, control means including a switch for stopping and permitting the operation of the press operated by said sensing means so that with the projection in an extended position the switch is in one position to permit press operation and so that with the projection in a depressed position the switch is in another position to stop press operation whereby press operation is permitted only when the dummy block is present and properly orientated with its front face forward and its rear face rearward and aligned in proper position for insertion into the container.

10. In combination with an extrusion press ram,

' dummy block sensing and control means comprising a projection member in the front face of the ram, a switch, interconnecting means interconnecting said projection member and said switch whereby said switch is in one position when said projection member is in a first position to permit press operation and said switch is in another position when said projection member is in a second position to stop press operation.

11. In combination with an extrusion press ram, dummy block sensing and control means comprising a projection member extending from the front face of the ram, a switch, interconnecting means interconnecting said projection member and said switch whereby said switch is in one position when said projection member is in an extended position to permit press operation and said switch is in another position when said projection member is in a depressed position to stop press operation.

12. In combination with an extrusion press ram, dummy block sensing and control means comprising a projection member extending from the front face of the ram, a mechanically operated switch, interconnecting means interconnecting said projection member and said switch, said interconnecting means including a first rod aligned substantially parallel to the ram axis, a pivot block, and a second rod aligned in a plane at substantially right angles to said ram axis whereby the movement of said projection member as it is depressed is mechanically transmitted to said switch.

13. In combination with an extrusion press ram, dummy block sensing and control means comprising a projection member extending from the front face of the ram, a pneumatic switch adapted for responding to pressure changes, interconnecting means interconnecting said projection member and said switch including a pneumatic line extending between said switch and said projection member, a metered supply of air to said line, a valve for venting said line, a rod interconnecting said projection member and said valve, whereby said switch is in one position when said projection member is in an extended position and said valve closed to confine air in said line and said switch is in another position when said projection member is in a depressed position and said valve opened to vent said line.

14. An extrusion press including a container, a ram, a billet loader supporting a billet having fiat ends and a dummy block both in position for insertion into said container having a flat front face and a counterbored rear face, a sensing means carried on the ram and adapted for discriminating between the dummy block rear face and the dummy block front face and between the dummy block rear face and a billet end, said sensing means including a projection extending forwardly from the ram and movable with respect to said ram, said counterbore adapted to receive said projection, said counterbore axially aligned with said projection, a switch for permitting and stopping press operations, interconnecting means interconnecting said projection member and said switch and operating means for juxtaposing the ram and thereby the sensing means including the projection member with the dummy block so that with the dummy block aligned with the ram and the container and properly oriented with its rear face toward the ram the said projection member maintains an extended location as the ram contacts the dummy block and moves it into the container behind the billet so that the switch is in one position to permit press operation and so that with the dummy block mis-aligned with the container and ram or oriented with its front face toward the ram, the projection member is depressed as the ram contacts or moves the dummy block, the switch is actuated to another position to stop press operation.

15. An extrusion press including a container, a ram, a billet loader supporting in elevated position for insertion into the container a billet having uncounterbored end faces and a dummy block having an uncounterbored front face and a counterbored rear face, the counterbore being centered in the rear face and adapted to receive a projection aligned with it, a sensing means carried on the ram and adapted for discriminating between the dummy block rear face and the dummy block front face and between the dummy block rear face and a billet end face, said sensing means including a projection extending forwardly from the ram and movable with respect to the ram and located through the center of the front ram end face so as to be axially aligned with said counterbore when the dummy block is elevated and in proper position for insertion into said container, control means including a switch for permitting and stopping press operation, interconnecting means interconnecting said projection member and said control means including said switch and operating means for juxtaposing the rain and thereby the sensing means including the projection member with the dummy block so that with the dummy block aligned with the container and its counterbore thereby aligned with the projection member and properly oriented with its rear face toward the ram, the projection member will maintain an extended position when the ram moves forward and contacts the dummy block and moves it into the container behind the billet and acts against it with extrusion pressure so that the switch will maintain one position to permit press operation and so that with the dummy block missing, misaligned with the container, or oriented with its front face toward the ram and projection member, the projection member will be depressed and the switch actuated to another position to stop press operation.

16. Safety apparatus for extrusion presses comprising an extrusion stem, a dummy block having a working face and an extrusion stern receiving face on opposite sides thereof, said dummy block extrusion stem receiving face having a recess therein, sensing means carried by said extrusion stem for sensing the correct position of said dummy block, said sensing means including an outwardly extending projection adapted to fit in said recess, and trip means controlled by said sensing means to provide a signal whereby the orientation of the dummy block may be detected.

17. The combination of claim 2 in which the combination further includes a pressure-sensitive switch and a fluid tube interconnecting said sensing means and said switch and in which said sensing means includes a projection member interconnected With said fluid tube whereby changes in the pressure of the fluid in said tube may be effected by movement of the projection member of the sensing means so that the switch is controlled by the position of the sensing means whereby the orientation of the dummy block be detected.

18. The safety apparatus of claim 16 in which the trip means is a switch and in whichsaid trip means and said sensing means are interconnectedby a column of air within a pneumatic tube.

References Cited by the Examiner UNITED STATES PATENTS 1,939,038 12/1933 Bower et al 29-38 2,083,312 6/1937 Brown et a1 29-38 2,925,176 2/1960 Wyngaert 2079 2,976,991 3/1961 De Matteo 2071.3

CHARLES W. LANHAM, Primary Examiner.

10 M. V. BRINDISI, Examiner.

E. D. OCONNOR, H. D. HOINKES,

Assistant Examiners. 

1. IN COMBINATION WITH AN EXTRUSION PRESS HAVING A BILLET LOADER, A RAM AND A CONTAINER; A DUMMY BLOCK HAVING A FRONT FACE, A REAR FACE, AND SENSING MEANS MOUNTED ON THE PRESS FOR DISCRIMINATING BETWEEN SAID FRONT AND REAR FACES WHEREBY THE ORIENTATION OF THE DUMMY BLOCK MAY BE DETECTED. 